Filler neck closure cap

ABSTRACT

A push-on filler neck cap for a fill passageway of a tank. The cap is provided with a push top and a dependent housing sized to fit within the fill passageway and with a fill passageway seal that is located at the lower inserted end of the housing and wherein the .[.can.]. .Iadd.cap .Iaddend.is also provided with a restraining mechanism located between the push top and the fill passageway .[.seat.]. .Iadd.seal .Iaddend.for securing the cap to the passageway in a sealed manner. The restraining mechanism is defined by a plurality of lugs which: 1) engage into a recess in the fill passageway; 2) pivot outward from the housing to engage the recess in response to movement of a spring biased lever pivotedly mounted to the push top with the recess; and (3) are biased to pivot outwardly for engagement with the recess by a spring located within the housing, which spring also urges the seal into its sealing relationship within the fill passageway.

BACKGROUND AND SUMMARY OF THE INVENTION

This present invention relates to tank filler neck caps and,particularly, to a push-on filler neck cap. More particularly, thepresent invention relates to a .Iadd.vehicle .Iaddend.filler neck capincluding an attachment mechanism for enabling a user to attach the capto the filler neck quickly and easily and establish a sealed connectionbetween the cap and the filler neck.

Conventional caps for closing the filler neck of a vehicle fuel tanktypically include a closure member for closing the mouth of the fillerneck and a handle for turning the closure member to mount the closuremember in the filler neck. Partial-turn cam-on caps and multiple-turnthreaded caps are well-known types of caps for use in closing fillernecks. See, for example, U.S. Pat. Nos. 4,887,733 to Harris and3,820,680 to Friend. Although turn-to-install caps are currently inwidespread use, it would be desirable to provide an alternative cap thatis simpler to install on and remove from a filler neck.

More and more vehicle drivers are using the self-service bays atgasoline stations and filling their own fuel tanks. Some people havefound that it is difficult to remove and install a conventionalpartial-turn or multiple-turn filler neck cap during refueling. A capthat is readily installable on and removable from a filler neck by auser without a lot of effort and that is configured to establish asturdy sealed connection between the cap and the filler neckconsistently during use would be a welcomed improvement overconventional caps.

What is needed is a push-on filler neck cap that can be installed easilyin the fill passageway of a filler neck. Once installed, a sealed liquidfuel and fuel vapor barrier would be in place near the mouth of thefiller neck. Ideally, such a push-on cap would be provided with acap-release mechanism that is easy to manufacture, assemble, and use.

According to the present invention, a push-on cap is provided forengaging a .Iadd.vehicle .Iaddend.filler neck. The cap includes ahousing sized to fit into a fill passageway in the filler neck andclosure means for closing the filler neck. The closure means is coupledto an axially inner end of the housing. The cap further includes meansfor pushing the housing and closure means as a unit into the fillpassageway to seat the closure means on a seal-receiving seat providedin the fill passageway in spaced-apart relation to the open mouth of thefiller neck. The pushing means is coupled to the axially outer end ofthe housing.

The cap further includes means for retaining the housing and the closuremeans in a filler neck-closing position in the fill passageway duringinstallation of the cap. The retaining means includes at least oneretaining lug mounted on the housing for pivotable movement between aprojected position fitting into a cap-retention cavity formed in thefiller neck and a retracted position away from the cap-retention cavityduring movement of the housing into and out of the fill passageway. Theretaining means also includes spring means for automatically yieldablybiasing each retaining lug toward its projected position so that eachretaining lug snaps automatically from its retracted position to itsprojected position in the cap-retention cavity during push-oninstallation of the cap on the filler neck. Thus, the housing andclosure means are automatically retained in the fill passageway duringinstallation of the cap.

In preferred embodiments, three pivotable retaining lugs are mountedaround the circumference of a cylindrically shaped housing. Eachretaining lug includes a radially outwardly extending locking arm, acentral pivot axis, and a radially inwardly extending toggle arm. Eachlocking arm is configured to fit into the cap-retention cavity formed inthe filler neck upon pivoting movement of the retaining lugs to theirprojected positions. The toggle arms are used to pivot the retaininglugs about their pivot axes to project the locking arms in radiallyoutward directions into the cap-retention cavity as soon as the cap ispushed far enough into the fill passageway of the filler neck.Illustratively, the filler neck is formed to include a singlering-shaped cap-retention cavity. Alternatively, the filler neck couldbe formed to include a separate cap-retention cavity for each retaininglug.

A lug actuator is mounted for vertical movement in an interior region ofthe housing and includes a downwardly opening cup-shaped part. Thespring means has an upper end extending into the cup-shaped part of thelug actuator and a lower end acting against the closure means. The lugactuator also includes means around the cup-shaped part for moving thetoggle arms of the retaining lugs to pivot the retaining lugs abouttheir pivot axes between their projected and retracted positions. Thespring means is positioned to push upwardly against the lug actuator sothat it moves the toggle arms automatically to pivot the locking armsinto the cap-retention cavity during installation of the cap in thefiller neck.

The cap also includes a control mechanism for releasing the retainingmeans to allow a user to withdraw the cap from the filler neck.Illustratively, the control mechanism includes a vertical stem on thetop of the cup-shaped portion of the lug actuator. The housing is formedto include a stem-receiving aperture. The stem moves up and down in thataperture during vertical movement of the lug actuator in the housing.The control mechanism also includes a cap-release lever pivotablymounted to an outer shell coupled to the axially outer end of thehousing and a cam on the cap-release lever in engagement with a camfollower on the stem of the lug actuator. This cam mechanism allows auser to move the lug actuator manually so that the retaining lugs arepivoted to their retracted positions whenever the user wishes to removethe cap from the filler neck.

To remove the cap from the filler neck, a user first pivots thecap-release lever from a horizontal cap-retaining position to a verticalcap-releasing position. This movement causes the cam on the cap-releaselever to turn and allow the upwardly biased lug actuator to movedownwardly in the housing. Such downward movement of the lug actuatorautomatically pivots each retaining lug to its retracted position todisengage the cap-retaining means in the filler neck. The user is nowfree to lift on the handgrip provided on the outer shell to withdraw thehousing and closure means as a unit from the fill passageway.

Additional objects, features, and advantages of the invention willbecome apparent to those skilled in the art upon consideration of thefollowing detailed description of preferred embodiments exemplifying thebest mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a sectional view of a cap according to the present inventionshowing a housing mounted in a fill passageway of a filler neck andretaining lugs pivotably mounted on the housing and spring-biased to fitinto a lug-receiving undercut formed in the filler neck to retain thecap in a sealed fill passageway-closing position in the filler neck;

FIG. 2 is a view of the cap of FIG. 1 showing a cap-release lever afterit has been pivoted to its vertical position to pivot the retaining lugsout of the undercut to their respective positions and showing an upperportion of the cap after it has been moved upwardly a short distance inthe fill passageway away from the underlying closure member and O-ringsealing gasket to raise the retracted retaining lugs above thelug-receiving undercut;

FIG. 3 is a view showing further upward movement of the cap in the fillpassageway as it is being manually withdrawn from the filler neck;

FIG. 4 is a view of cap installation showing movement of the housing andclosure member into the fill passageway during installation of the capon the filler neck and showing pivoting of the retaining lugs inradially inward directions toward their retracted positions upon cammingengagement with a conical camming surface located at the mouth of thefiller neck;

FIG. 5 is a top plan view of the cap of FIG. 1 with portions broken awayto show a wide locking arm on one of the retaining lugs in thelug-receiving undercut formed in the filler neck and a narrow toggle lugon that retaining lug in engagement with a movable lug actuator andshowing a D-shaped lever pivotably mounted on the cap to controlmovement of the lug actuator and toggling of the retaining lugs duringrelease of the cap from its sealed filler neck-closing position;

FIG. 6 is a perspective view of a preferred embodiment of the pivotableretaining lug shown in FIG. 5;

FIG. 7 is a side elevation view of the cap of FIG. 1 showing thehandgrip on the outer shell, a two-part housing, two of the pivotableretaining lugs carried on the housing, the lug actuator-biasing springinside the housing, the closure member, and an O-ring sealing gasket onthe closure member; and

FIG. 8 is a bottom plan view of the cap of FIG. 7 showing the threepivotable retaining lugs uniformly spaced apart about the circumferenceof the housing and seven inlet apertures into a pressure-relief andvacuum-relief valve assembly mounted in the closure member.

DETAILED DESCRIPTION OF THE DRAWINGS

A push-on cap 10 in accordance with the present invention is mounted in.Iadd.a vehicle .Iaddend.filler neck 12 to close a fill passageway 14.Iadd.defined by an inside wall 11 .Iaddend.formed in filler neck 12.Cap 10 includes .Iadd.a closure 15 having an axially inner end 17, anaxially outer end 19, and a side wall 41. The closure 15 is formed forclosing the vehicle filler neck 12. Closure 15 includes .Iaddend.anupper housing portion 16, a lower housing portion 18 rigidly connectedto upper housing portion 16, .Iadd.a closure retainer apparatus 21configured to engage the filler neck 12 when the cap 10 is installed inthe filler neck 12 to block removal of the closure 15 from the fillerneck 12, .Iaddend.and .[.a.]. .Iadd.an end .Iaddend.closure member 20coupled to lower housing portion 18 to allow limited relative movementbetween .Iadd.the end .Iaddend.closure member 20 and lower housingportion 18. An O-ring sealing gasket 22 is carried on the .Iadd.end.Iaddend.closure member 20 and configured to seal against .Iadd.asealing surface formed by .Iaddend.an annular seal-receiving seat 24situated to lie in the fill passageway 14 in spaced-apart relation tothe open mouth 26 of filler neck 12. .Iadd.The O-ring sealing gasket 22is annular in shape and engages the filler neck 12 and the closure 15 sothat the sealing gasket is compressed between the closure 15 and thefiller neck 12 to sealingly engage the closure 15 and the filler neck 12and form a seal therebetween. As best shown in FIG. 1, sealing gasket 22includes a first portion 23 engaging the closure 15 and a second portion25. The closure member 20 includes a groove 27 that receives the firstportion 23 of the sealing gasket 22 therein. .Iaddend.

The filler neck 12 is configured to receive and retain the cap 10 in asealed position closing the fill passageway 14 as shown in FIG. 1. Thefiller neck 12 is formed to include .Iadd.a mouth 29, .Iaddend.anaxially inwardly diverging conical camming surface 28 .[.and.]. a singlering-shaped undercut cap-retention cavity 30. This cavity 30 isconfigured to open into the fill passageway 14 and lie between theconical camming surface 28 and the radially inwardly projectingseal-receiving seat 24. .Iadd.Illustratively, the axial distance betweenthe mouth 29 and the seal-receiving seat 24 is a distance X, as shown byline 31. The radial diameter of the inside wall 11 axially inwardly ofthe cavity 30 and axially outwardly of the seal-receiving seat 24 is adistance Y. Y is about 1.11X and illustrated by line 33. Moreover, asshown in FIG. 1, the axial distance between an outermost portion 35 ofthe closure retainer apparatus 21 that engages a curved downwardlyfacing retaining wall 138 and an outermost portion 37 of the secondportion 25 is a distance Z. Z is about 0.69X and illustrated by line 39..Iaddend.The cap-retention cavity 30 is configured in the mannerdescribed below to receive .Iadd.the closure retainer apparatus 21 thatcomprises .Iaddend.pivotable .Iadd.ramped .Iaddend.cap-retaining lugs 32mounted on the lower housing portion 18 and hold the cap 10 in itsfiller neck-closing position shown in FIG. 1. In another embodiment (notshown), the filler neck 12 is formed to include a separate cap-retentioncavity for each cap-retaining lug. The filler neck 12 also includes areduced-diameter aperture 34 that is positioned in the fill passageway14 below the seal-receiving seat 24 and sized to receive only asmall-diameter nozzle (not shown for dispensing unleaded fuel. The cap10 further includes an outer shell 36 attached to the axially outer endof the upper housing portion 16. The outer shell 36 includes a top wall38 formed to include a central slot-like aperture 40 and an annular sidewall 42 formed to provide a handgrip. The side wall 42 also includes aplurality of circumferentially spaced-apart tangs 44 that snap onto anupper plate 46 on the upper housing portion 16 to retain the outer shell36 in place on the upper housing portion 16 as shown in FIGS. 1 and 8.Illustratively, the outer shell 36 is coupled to upper plate 46 to allowfor freely spinning movement of the outer shell about vertical axis 47(FIG. 1) relative to upper housing portion 16.

The upper housing portion 16 includes a central core 48 surrounded byupper plate 46 and formed to include a cam-receiving depression 50 and astem-receiving aperture 52. The stem-receiving aperture 52 provides apassageway between the cam-receiving depression 50 and an interiorregion 54 of the housing 16, 18. The upper and lower housing portions16, 18 cooperate to define three lug-mounting slots 56 that areuniformly spaced apart about the circumference of housing 16, 18 andarranged so that each of the slots 56 confronts the cap-retention cavity30 formed in the filler neck 12 upon movement of the cap 10 to thefiller neck-closing position shown in FIG. 1. The lower housing portion18 is formed to include arm-receiving channels 58 as shown in FIG. 1 topermit limited movement of closure member 20 relative to lower housingportion 18.

As shown in FIGS. 1, 5, and 6, each retaining lug 32 includes a widelocking arm 60, a central body 61, pivot axle 62 appended to the centralbody 61, and a narrow toggle arm 64. Illustratively, each retaining lug32 is a one-piece molded plastic part as shown in FIG. 6. It will beunderstood that retaining lug 32 could also be a multi-piece assemblyincluding, for example, a separate pivot axle. The lower housing portion18 and upper housing portion 16 are formed to include cradle means 66for supporting and retaining each pivot axle 62 to mount each.Iadd.ramped .Iaddend.retaining lug 32 in one of the lug-mounting slots56 formed in the housing 16, 18. Illustratively, nesting cradles areformed in the lower housing portion 18 and axle-retaining fingers areformed in the upper housing portion 16. Each retaining lug 32 is free topivot about its pivot axle 62 between a radially outwardly extendingprojected position fitting in the cap-retention cavity 30 as shown, forexample, in FIG. 1 and a radially inwardly extending retracted positionaway from the cap-retention cavity 30 as shown, for example, in FIG. 2.

A lug actuator 72 is positioned in the interior region 54 of housing 16,18 and allowed to move vertically in the interior region 54 duringinstallation and removal of the cap 10. Lug actuator 72 includes aninverted cup-shaped member 74, an upstanding stem 76, and means 78 forgripping each of the toggle arms 64 as shown in FIG. 1. The cup-shapedmember 74 is arranged to open downwardly toward the closure member 20and includes a concave top wall 80 and a cylindrical side wall 82. Theupstanding stem 76 has a foundation end rooted in the concave top wall80 and a free end 84. The free end 84 is arranged to extend through thestem-receiving aperture 52 formed in the upper housing portion 16 andformed to define a cam follower 86.

A plurality of gripping means 78 are formed in spaced-apart relationabout the circumference of the cylindrical side wall 82 of thecup-shaped member 74. .[.Each.]. .Iadd.The gripping means 78 includes atoggle arm seat 61 supporting the toggle arm 64 and a toggle arm cover63. The toggle arm 64 is sandwiched between the seat 61 and cover 63 sothat each .Iaddend.gripping means 78 is configured to move a toggle arm64 to pivot the locking arm 60 appended to the toggle arm 64 about itspivot axle 62 between its projected and retracted positions.Illustratively, the gripping means 78 are configured to engage and moveall of the toggle arms 64 simultaneously so that the retaining lugs 32can be moved together either in radially outward directions to reachtheir projected positions or in radially inward directions to reachtheir retracted positions.

The closure member 20 is formed to include a plurality of inlet openings88 in a lower end 90 located below O-ring sealing gasket 22 as shown inFIG. 1 so that a pressure-relief and vacuum-relief valve assembly 92mounted in a cavity formed in the closure member 20 can regulate thepressure in lower portion 93 of fill passageway 14 while the cap 10 isseated in its sealed filler neck-closing position. Valve assembly 92includes a pressure-relief valve 94, a vacuum-relief valve 96, a supportplate 98 appended to closure member 20 and formed to include ventaperture 110, and springs 112, 114 for yieldably biasing the valves 94,96 to their normally closed positions. Spring 112 engages support plate98 and pressure-relief valve 94 to bias the pressure-relief valve 94against an annular valve seat formed on closure member 20. Spring 114engages a plate attached to vacuum-relief valve 96 and pressure-reliefvalve 94 to bias the vacuum-relief valve 96 against an annular valveseat formed on the underside of pressure-relief valve 94.

A compression spring 116 is positioned inside the interior region 54 ofhousing 16, 18 and arranged so that its axially inner end engagessupport plate 98 and its axially outer end extends into the cup-shapedmember 74 of the lug actuator 72. As shown in FIG. 1, the ceiling insidecup-shaped member 74 is dome-shaped to provide a seat for engaging andretaining the axially outer end of the cylindrical compression spring116. When assembled, the housing 16, 18 and the closure .Iadd.end.Iaddend.member 20 are held together for limited relative movementtherebetween.Iadd.. The end closure member 20 includes a cup-shapedmouth 51, snap arms 118, and the groove 27 sized to receive the seal 22therein. The end closure member 20 is movably held on the housing 16, 18.Iaddend.by engagement of snap arms 118 on closure member 20 in theslots 58 formed in the lower housing portion 18. The cap 10 isconfigured so that the compression spring 116 acts against the supportplate 98 to apply a load to the lug actuator 72 that is sufficient topivot all of the retainer lugs 32 normally to their projected positions.

As shown in FIGS. 1 and 5, a cap-release lever 120 is provided to enablea user to pivot the retaining lugs 32 from their cap-retaining projectedpositions engaging the filler neck 12 to their cap-releasing retractedpositions disengaging the filler neck 12 and thereby begin to remove thecap 10 from the filler neck 12. Cap-release lever 120 includes aD-shaped lever handle 122 having a finger grip 124, a lever body 126,and pivot pins 128. The cap-release lever 120 is mounted to outer shell36 for pivotable movement between a horizontal cap-retaining position asshown, for example, in FIG. 1 and a vertical cap-releasing position asshown, for example, in FIG. 2. As shown in FIG. 5, the outer shell 36 isformed to include a lever handle-receiving recess 130 to receive theD-shaped lever handle 122 in its horizontal position.

Lever body 126 is formed to include a cam surface 132 arranged to engagethe cam follower 86 provided on the free end 84 of the lug actuator stem76. Compression spring 116 acts against the lug actuator 72 to yieldablyload the cam follower 86 against cam surface 132. During pivoting ofcap-release lever 120, the cam surface 132 engages the cam follower 86and imparts movement to the lug actuator 72.

In use, the cap 10 is released from its filler neck-closing position infill passageway 14 by pivoting the cap-release lever 120 in thefollowing manner. The user lifts the finger grip 124 to pivot the leverhandle 122 in direction 134 about pivot pins 128 as shown in FIGS. 1 and2. Pivoting movement of lever handle 122 in direction 134 causes the camsurface 132 to push against the cam follower 86 and drive the lugactuator 72 downwardly inside housing 16, 18. This downward movement oflug actuator 72 compresses preloaded main compression spring 116 furtherand pivots the toggle-retaining lugs 32 inward and out of the undercutcap-retention cavity 30 formed in the filler neck 12. As soon as thecurved top surface 136 of each locking arm 60 disengages .[.a.]..Iadd.the .Iaddend.curved downwardly facing retaining wall 138 of fillerneck 12 in the cap-retention cavity 30, the preloaded main compressionspring 116 drives the retaining lugs 32 upwardly past the undercutcap-retention cavities 30 to allow the user to withdraw the cap 10manually from the filler neck 12 as shown in FIG. 3.

During installation of cap 10 in filler neck 12, the closure member 20and housing 16, 18 are inserted as a unit into fill passageway 14through the filler neck mouth 26 as shown in FIG. 4. If one ring-shapedcap-retention cavity 30 is provided, then the cap 10 can be pushed intofill passageway 14 without first rotating the cap 10 about vertical axis47 to a predetermined position. However, if a cap-retention cavity isprovided for each retaining lug 32, it will be necessary for a user toorient the cap 10 relative to filler neck 12 by rotating the cap 10about axis 47 to an installation position matching up the position ofthe retaining lugs 32 to the position of the underlying cap-retentioncavities.

The user pushes on the outer shell 36 while the cap-release lever 120 isretained in its horizontal cap-retaining position to move the cap 10further into fill passageway 14. As shown in FIG. 4, a cam follower 140on each retaining lug 32 contacts conical camming surface 28 at the openmouth 26 of filler neck 12 to cause the retaining lugs 32 to be pivotedradially inwardly automatically to their retracted positions. As soon asthe cap 10 is pushed far enough into fill passageway 14, thespring-loaded retaining lugs 32 pivot radially outwardly to snapautomatically into the cap-retention cavity 30. The spring 116 thenurges the O-ring sealing gasket 22 into sealing engagement with theseal-receiving seat 24 formed in the filler neck 12 as shown in FIG. 1.Once the fill passageway 14 is closed by closure member 20, excesspressure in lower portion 93 of fill passageway 14 is vented bypressure-relief valve 94 to the atmosphere and vacuum-relief valve 96vents air into the lower portion 93 to relieve excess vacuum conditionstherein.

If the installation stroke is insufficient to latch the toggle-typeretaining lugs 32 and the user lets go of the outer shell 36, then thespring-loaded retaining lugs 32 will ordinarily be driven by lugactuator 72 and spring 116 out of fill passageway 14 and into the user'shand. Advantageously, this step provides a signal to the user that thecap 10 did not seat in the filler neck 12 and that it is necessary toonce again push the cap 10 into fill passageway 14 until it snaps intoits filler neck-closing position.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of the invention as described and defined in thefollowing claims.

I claim:
 1. A cap for use in a filler neck of a tank, the filler neckbeing formed to include an outer mouth, a fill passageway communicatingwith the outer mouth, a cap-retention cavity opening into the fillpassageway, and a seal-receiving seat lying in the fill passageway inspaced-apart relation to the outer mouth, the cap comprisinga housingsized to fit into the fill passageway, the housing having an axiallyinner end and an axially outer end, closure means for closing the fillerneck, the closure means being coupled to the axially inner end of thehousing, means for pushing the housing and closure means into the fillpassageway to seat the closure means on the seal-receiving seat, thepushing means being attached to the axially outer end of the housing,and means for retaining the housing and the closure means in a fillerneck-closing position in the fill passageway so that the closure meanssealingly engages the seal-receiving seat to close the fill passageway,the retaining means including at least one retaining lug, means forpivotably coupling each retaining lug to the housing for pivotingmovement between a projected position fitting into the cap-retentioncavity and a retracted position lying outside the cap-retention cavityduring movement of the housing into and out of the fill passageway, andspring means for yieldably biasing each retaining lug toward itsprojected position so that it snaps automatically from its retractedposition into the cap-retention cavity to retain the housing and closuremeans in the filler neck-closing position during installation of the capon the filler neck.
 2. The cap of claim 1, wherein the housing is acylindrical sleeve having an interior region and carrying the.[.mounting.]. .Iadd.retaining .Iaddend.means and the spring means ispositioned to extend into the interior region of the cylindrical sleeve.3. The cap of claim 2, wherein the retaining means includes a pluralityof retaining lugs arranged in spaced-apart relation around acircumference of the cylindrical sleeve and in radially outwardlyspaced-apart relation to said cylindrical sleeve.
 4. The cap of claim 1,wherein the housing is a cylindrical sleeve and the retaining meansincludes a plurality of retaining lugs arranged in spaced-apart relationabout a circumference of the cylindrical sleeve and coupled to thecoupling means to pivot in radially inward and outward directions withrespect to the cylindrical sleeve during movement of the retaining lugsbetween the projected and retracted positions and during movement of thehousing into and out of the fill passageway.
 5. The cap of claim 4,further comprising control means for pivoting the retaining lugssimultaneously in radially inward directions from their projectedpositions to their retracted positions, the control means being mountedon the axially outer end of the housing.
 6. The cap of claim 5, whereinthe pushing means includes a handgrip cover mounted on the axially outerend of the housing, the handgrip cover is formed to include an aperture,and the control means extends through the aperture.
 7. The cap of claim5, wherein the control means includes a movable lug actuator in thehousing and means for moving the lug actuator in the housing and the lugactuator includes means for engaging the retaining lugs to cause theretaining lugs to pivot in response to movement of the lug actuator inthe housing.
 8. The cap of claim 4, further comprising a controller,means for mounting the controller on the housing for movement between acap-retaining position and a cap-releasing position, and means forpivoting the retaining lugs between their projected and retractedpositions in response to movement of the controller relative to thehousing.
 9. The cap of claim 8, wherein the mounting means includes anouter shell coupled to the axially outer end of the housing, thepivoting means includes a movable lug actuator positioned to lie in thehousing and configured to engage the retaining lugs, and the controlleris a pivotable lever carried on the outer shell and including means formoving the movable lug actuator in the housing to control pivotingmovement of the retaining lugs.
 10. The cap of claim 8, wherein eachretaining lug includes a toggle arm engaging the pivoting means and alocking arm configured to fit into the cap retention cavity, thecontroller is a lever, the mounting means includes an outer shellcoupled to the axially outer end of the housing and means for supportingthe lever for pivotable movement relative to the outer shell, and thelever includes a grip handle and cam means for moving the pivoting meansrelative to the housing against the toggle arms to pivot each retaininglug to move the locking arms into the cap-retention cavity in responseto pivoting movement of the lever relative to the outer shell.
 11. Thecap of claim 8, wherein the spring means engages the closure means andthe pivoting means.
 12. The cap of claim 1, wherein the closure meansincludes a closure member, a sealing gasket on the closure member, andmeans for connecting the closure member to the housing to permitrelative movement therebetween in the fill passageway so that thehousing is free to move in an axially inward direction into the fillpassageway and relative to the closure member upon seating of thesealing gasket on the seal-receiving seat of the filler neck.
 13. A capfor use in a filler neck of a tank, the filler neck being formed toinclude an outer mouth, a fill passageway communicating with the outermouth, a cap-retention cavity opening into the fill passageway, and aseal-receiving seat lying in the fill passageway in spaced-apartrelation to the outer mouth, the cap comprisinga housing sized to fitinto the fill passageway, the housing having an axially inner end and anaxially outer end, closure means for closing the filler neck, theclosure means being coupled to the axially inner end of the housing,means for pushing the housing and closure means into the fill passagewayto seat the closure means on the seal-receiving seat, the pushing meansbeing coupled to the axially outer end of the housing, and means forretaining the housing and the closure means in a filler neck-closingposition in the fill passageway so that the closure means sealinglyengages the seal-receiving seat to close the fill passageway, theretaining means including at least one retaining lug, means for mountingeach retaining lug to the housing for movement between a projectedposition fitting into the cap-retention cavity and a retracted positionlying outside the cap-retention cavity during movement of the housinginto and out of the fill passageway, and spring means for yieldablybiasing each retaining lug toward its protected position so that itsnaps automatically from its retracted position into the cap-retentioncavity to retain the housing and closure means in the fillerneck-closing position during installation of the cap on the filler neck,the housing being a cylindrical sleeve having an interior region andcarrying the mounting means and the spring means being positioned toextend into the interior region of the cylindrical sleeve, the closuremeans including a closure member and a sealing gasket on the closuremember, the retaining means further including a movable lug actuatorcoupled to each retaining lug, and the spring means including acompression spring having an axially inner end engaging the closuremember and an axially outer end engaging the lug actuator.
 14. The capof claim 13, further comprising control means for moving the lugactuator against the compression spring to move each retaining lug fromits projected position to its retracted position to permit withdrawal ofthe housing and closure means from the fill passageway.
 15. The cap ofclaim 13, wherein the lug actuator is positioned for movement in theinterior region of the housing and lies between the pushing means andthe compression spring.
 16. A cap for use in a filler neck of a tank,the filler neck being formed to include an outer mouth, a fillpassageway communicating with the outer mouth, a cap-retention cavityopening into the fill passageway, and a seal-receiving seat lying in thefill passageway in spaced-apart relation to the outer mouth, the capcomprisinga housing sized to fit into the fill passageway, the housinghaving an axially inner end and an axially outer end, closure means forclosing the filler neck, the closure means being coupled to the axiallyinner end of the housing, means for pushing the housing and closuremeans into the fill passageway to seat the closure means on theseal-receiving .[.so.]. .Iadd.seat, .Iaddend.the pushing means beingcoupled to the axially outer end of the housing, and means for retainingthe housing and the closure means in a filler neck-closing position inthe fill passageway so that the closure means sealingly engages theseal-receiving seat to close the fill passageway, the retaining meansincluding at least one retaining lug, means for mounting each retaininglug to the housing for movement between a .[.protected.]..Iadd.projected .Iaddend.position fitting into the cap-retention cavityand a retracted position lying outside the cap-retention cavity duringmovement of the housing into and out of the fill passageway, and springmeans for yieldably biasing each retaining lug toward its projectedposition so that it snaps automatically from its retracted position intothe cap-retention cavity to retain the housing and closure means in thefiller neck-closing position during installation of the cap on thefiller neck, the closure means including a closure member, a sealinggasket on the closure member, and means for coupling the closure memberto the housing to permit relative movement therebetween in the fillpassageway so that the housing is free to move in an axially inwarddirection into the fill passageway and relative to the closure memberupon seating of the sealing gasket on the seal-receiving seat of thefiller neck, the retaining means further including a movable lugactuator arranged to lie in the housing and contact each retaining lug,the spring means including a compression spring engaging the closuremember and the lug actuator, and the housing including means for movingthe lug actuator toward the closure member to compress the compressionspring during movement of the housing into the fill passageway andmovement of the retaining lugs to their projected positions.
 17. The capof claim 16, further comprising control means for moving the lugactuator against the compression spring to compress the compressionspring and pivot the retaining lugs to their retracted positions so thatthe housing is allowed to move relative to the closure means under aforce applied by the compression spring and the housing and closuremeans are removable from the fill passageway.
 18. The cap of claim 16,wherein the lug actuator further includes a cup-shaped member engagingthe compression spring and having a cylindrical side wall extendingdownwardly toward the sealing gasket and a gripping means appended tothe cylindrical side wall and the gripping means is configured to engageand move the retaining lugs.
 19. A cap for use in a filler neck of atank, the filler neck being formed to include an outer mouth, a fillpassageway communicating with the outer mouth, and a seal-receiving seatlying in the fill passageway in spaced-apart relation to the outermouth, the cap comprisingclosure means for closing the filler neck, theclosure means including a sealing gasket for abutting the seal-receivingseat without contacting the outer mouth, a housing coupled to theclosure means and sized to extend into the fill passageway through theopen mouth, means for retaining the housing and the closure means in thefill passageway, the retaining means being mounted on the housing formovement between a filler neck-engaging position and a fillerneck-releasing position, control means for moving the retaining meansfrom its filler neck-engaging position to its filler neck-releasingposition, and spring means for urging the sealing gasket of the closuremeans against the seal-receiving seat of the filler neck to establish aseal between the closure means and the filler neck, the spring meansengaging the control means and the closure means.
 20. The cap of claim19, wherein the retaining means includes at least one retaining lug andmeans for pivotably mounting each retaining lug on the housing forpivotable movement about a pivot axis between a filler neck-engagingposition and a filler neck-releasing position.
 21. The cap of claim 20,wherein the control means includes a lever pivotably mounted on thehousing and a movable lug actuator in the housing engaging the at leastone retaining lug, and means for moving the lug actuator to pivot the atleast one retaining lug in response to pivoting movement of the leverrelative to the housing.
 22. The cap of claim 20, wherein the housingincludes a cylindrical sleeve, the retaining means includes a pluralityof retaining lugs arranged in spaced-apart relation about thecircumference of the cylindrical sleeve and arranged to pivot inradially inward and outward directions with respect to the cylindricalsleeve, and the control means includes a controller above the housingand a lug actuator positioned to move in the cylindrical sleeve andconfigured to include means for pivoting the retaining lugssimultaneously in one of the radially inward direction and radiallyoutward direction to move the retaining lugs between their fillerneck-engaging and filler neck-releasing positions in response tomovement of the controller relative to the housing.
 23. The cap of claim22, wherein the filler neck is formed to include an inner wall definingthe fill passageway and cavity means in the inner wall for receiving theretaining lugs upon movement of the retaining lugs in radially outwarddirections to their filler neck-retaining positions.
 24. The cap ofclaim 22, wherein each retaining lug includes a toggle arm engaging thepivoting means of the actuator and a locking arm configured to engage anundercut cavity formed in the filler neck upon pivoting movement of theretaining lug to its filler neck-engaging position.
 25. The cap of claim22, wherein the controller includes a lever, the housing includes meansfor mounting the lever to the housing for pivotable movement between ahorizontal cap-retaining position and a vertical cap-releasing position,and the lever includes means for moving the lug actuator further intothe cylindrical sleeve to pivot the retaining lugs in radially inwarddirections to their filler neck-releasing positions in response tomovement of the lever relative to the housing from its horizontalcap-retaining position to its vertical cap-releasing position.
 26. Thecap of claim 19, wherein the filler neck is formed to includelug-receiving cavity means for receiving each retaining lug and thecontrol means includes means for pivoting the retaining lugssimultaneously to cause each retaining lug to pivot into thelug-receiving cavity means to establish the filler neck-engagingposition and out of the lug-receiving cavity means to establish thefiller neck-releasing position.
 27. The cap of claim 26, wherein eachretaining lug includes a locking arm and a toggle arm, the pivotingmeans includes a lug actuator coupled to the toggle arms and arranged toslide in opposite directions in an interior region of the housing, andthe control means further includes means coupled to the housing formoving the lug actuator in a first direction further into the interiorregion of the housing to pivot the retaining lugs so that the lockingarms of the retaining lugs move out of the lug-receiving cavity meansformed in the filler neck and the housing and closure means is removablefrom the fill passageway.
 28. The cap of claim 19, wherein the fillerneck includes means for automatically camming the retaining means to itsfiller neck-releasing position during insertion of the housing andclosure means into the fill passageway.
 29. The cap of claim 28, whereinthe control means includes a movable lug actuator positioned to move inthe housing and configured to include means for transmitting a springforce generated by the spring means to the retaining means to yieldablybias the retaining means to its filler neck-engaging position upondisengagement of the retaining means and the camming means.
 30. The capof claim 29, wherein the camming means includes an axially inwardlyconverging conical surface at the outer mouth of the filler neck, thefiller neck is formed to include cavity means for receiving theretaining means in its filler neck-engaging position to lock the housingand closure means in a fixed position closing the fill passageway, thecavity means is located between the axially inwardly converging conicalsurface and the seal-receiving seat, the retaining means includes atleast one retaining lug and means for pivotably mounting each retaininglug on the housing for pivotable movement about a pivot axis, themovable lug actuator includes a cup-shaped member engaging the springmeans and means on the cup-shaped member for pivoting each retaining lugabout its pivot axis into and out of the cavity means in response tomovement of the movable lug actuator in the fill passageway.
 31. A capfor use in a filler neck of a tank, the filler neck being formed toinclude an outer mouth, a fill passageway communicating with the outermouth, and a seal-receiving seat lying in the fill passageway inspaced-apart relation to the outer mouth, the cap comprisingclosuremeans for closing the filler neck, the closure means including a sealinggasket, a housing coupled to the closure means and sized to extend intothe fill passageway through the open mouth, means for retaining thehousing and the closure means in the fill passageway, the retainingmeans being mounted on the housing for movement between a fillerneck-engaging position and a filler neck-releasing position, controlmeans for moving the retaining means from its filler neck-engagingposition to its filler neck-releasing position, and spring means forurging the sealing gasket of the closure means against theseal-receiving seat of the filler neck to establish a seal between theclosure means and the filler neck, the spring means engaging the controlmeans and the closure means, the retaining means including at least oneretaining lug and means for pivotably mounting each retaining lug on thehousing for pivotable movement about a pivot axis between a fillerneck-engaging position and a filler neck-releasing position, the controlmeans including a lever pivotably mounted on the housing and a movablelug actuator in the housing engaging the at least one retaining lug, andmeans for moving the lug actuator to pivot the at least one retaininglug in response to pivoting movement of the lever relative to thehousing, each retaining lug including a toggle arm engaging the movablelug actuator and a locking arm configured to engage an undercut cavityformed in the filler neck upon pivoting movement of the retaining lug toits filler neck-engaging position.
 32. A cap for use in a filler neck ofa tank, the filler neck being formed to include an outer mouth, a fillpassageway communicating with the outer mouth, and a seal-receiving seatlying in the fill passageway in spaced-apart relation to the outermouth, the cap comprisingclosure means for closing the filler neck, theclosure means including a .[.seal.]. .Iadd.sealing .Iaddend.gasket, ahousing coupled to the closure means and sized to extend into the fillpassageway through the open mouth, means for retaining the housing andthe closure means in the fill passageway, the retaining means beingmounted on the housing for movement between a filler neck-engagingposition and a filler neck-releasing position, control means for movingthe retaining means from its filler neck-engaging position to its fillerneck-releasing position, spring means for urging the sealing gasket ofthe closure means against the seal-receiving seat of the filler neck toestablish a seal between the closure means and the filler neck, thespring means engaging the control means and the closure means, thefiller neck including means for automatically camming the retainingmeans to its filler neck-releasing position during insertion of thehousing and closure means into the fill passageway, and each retaininglug including a radially outwardly facing cam follower surface and thecamming means is a conical surface formed in the outer mouth of thefiller neck and positioned to engage the radially outwardly facing camfollower surface during insertion of the housing into the fillpassageway.
 33. A cap for use in a filler neck of a tank, the fillerneck being formed to include an outer mouth, a fill passagewaycommunicating with the outer mouth, and a seal-receiving seat lying inthe fill passageway in spaced-apart relation to the outer mouth, the capcomprisingclosure means for closing the filler neck, the closure meansincluding a sealing gasket, a housing coupled to the closure means andsized to extend into the fill passageway through the open mouth, meansfor retaining the housing and the closure means in the fill passageway,the retaining means being mounted on the housing for movement between afiller neck-engaging position and a filler neck-releasing position,control means for moving the retaining means from its fillerneck-engaging position to its filler neck-releasing position, springmeans for urging the sealing gasket of the closure means against theseal-receiving seat of the filler neck to establish a seal between theclosure means and the filler neck, the spring means engaging the controlmeans and the closure means, the filler neck including means forautomatically camming the retaining means to its filler neck-releasingposition during insertion of the housing and closure means into the fillpassageway, and the .[.filer.]. .Iadd.filler .Iaddend.neck being formedto include cavity means for receiving the retaining means in its fillerneck-engaging position and the cavity means being located between thecamming means and the seal-receiving seat.
 34. The cap of claim 33,wherein the filler neck has a longitudinal axis and includes an axiallydownwardly facing surface defining an upper wall of the cavity means andthe spring means bears on the control means to provide means for urgingthe retaining means upwardly into engagement with the axially downwardlyfacing surface.
 35. A cap for use in a filler neck of a tank, the fillerneck being formed to include an outer mouth, a fill passagewaycommunicating with the outer mouth, and a seal-receiving seat lying inthe fill passageway in spaced-apart relation to the outer mouth, the capcomprisingclosure means for closing the filler neck, the closure meansincluding a sealing gasket, a housing attached to the closure means andsized to extend into the fill passageway through the open mouth, thehousing being formed to include an interior region, means for retainingthe housing and the closure means in the fill passageway, the retainingmeans including at least one retaining lug, each retaining lug beingcoupled to the housing for pivotable movement between a fillerneck-engaging position and a filler neck-releasing position, controlmeans for moving the retaining means from its filler neck-engagingposition to its filler neck-releasing position, the control meansincluding an actuator movable in the interior region, and spring meansfor .[.during.]. .Iadd.urging .Iaddend.the sealing gasket of the closuremeans against the seal-receiving seat of the filler neck to establish aseal between the closure means and the filler neck, the spring meansengaging the actuator and the closure means, the actuator includingmeans for engaging each retaining lug, and the control means furtherincluding means for moving the actuator in the housing against thespring means to pivot each retaining lug from its filler neck-engagingposition to its filler neck-releasing position.
 36. The cap of claim 35,wherein the filler neck is formed to include a lug-receiving cavity forreceiving each retaining lug and an axially inwardly facing edgebordering the lug-receiving cavity, each retaining lug is sized to fitin the lug-receiving cavity in its filler neck-engaging position, andthe spring means acts against the engaging means of the actuator to urgeeach retaining lug into engagement with the axially inwardly facing edgeof the filler neck and against the closure means to urge the sealinggasket against the seal-receiving seat of the filler neck.
 37. The capof claim 36, wherein the moving means includes a lever including a camand the actuator includes a cam follower in engagement with the cam. 38.The cap of claim 36, wherein the moving means includes a lever and meansfor mounting the lever to the housing for pivotable movement relative tothe housing between a cap-retaining position and a cap-releasingposition, the actuator includes a cam follower, and the lever includescam means for camming the cam follower to move the actuator in thehousing and against the spring means so that each retaining lug ispivoted to its filler neck-releasing position upon pivoting of the leverto its cap-releasing position.
 39. A cap for use in a filler neck of atank, the .[.filer.]. .Iadd.filler .Iaddend.neck being formed to includean outer mouth, a fill passageway communicating with the outer mouth, acap-retention cavity opening into the fill passageway, and aseal-receiving seat lying in the fill passageway in spaced-apartrelation to the outer mouth, the cap comprisinga housing sized to fitinto the fill passageway, the housing having an axially inner end facinginto the fill passageway and an axially outer end facing away from thefill passageway, closure means for closing the filler neck, the closuremeans being coupled to the axially inner end of the housing, means forretaining the housing and the closure means in a filler neck-closingposition in the fill passageway so that the closure means sealinglyengages the seal-receiving seat to close the fill passageway, and springmeans for yieldably biasing the retaining means toward the fillerneck-closing position and the spring means including a compressionspring having an axially inner end facing into the fill passageway andengaging the closure means and an axially outer end facing away from thefill passageway and engaging the retaining means.
 40. The cap of claim39, further including means for pushing the housing and closure meansinto the fill passageway to seat the closure means on the seal-receivingseat, the pushing means being coupled to the axially outer end of thehousing.
 41. The cap of claim 39, wherein the retaining means furtherincludes means for mounting the retaining means to the housing formovement between a projected position fitting into the cap-retentioncavity and a retracted position lying outside the cap-retention cavityduring movement of the housing into and out of the fill passageway. 42.The cap of claim 41, wherein the retaining means further includes atleast one retaining lug, and the spring means biases the at least oneretaining lug toward its projected position so that it snapsautomatically from its retracting position into the cap-retention cavityto retain the housing and closure means in the filler neck-closingposition during installation of the cap in the filler neck. .Iadd.
 43. Acap engageable with a vehicle filler neck of a vehicle fuel tank whereinthe vehicle filler neck includes a mouth defining a fill passageway anda sealing surface positioned to lie in the fill passageway spaced apartfrom the mouth, the cap comprisinga closure for closing the vehiclefiller neck, the closure sized for insertion into the fill passagewayand having an axially inner end, an axially outer end, a side wall, andclosure retainer apparatus radially movable relative to the side wall,the closure retainer apparatus being configured to engage the vehiclefiller neck when the closure is installed in the vehicle filler neck toblock removal of the closure from the vehicle filler neck, a handlecoupled to the axially outer end of the closure for moving the closurerelative to the vehicle filler neck, and a seal mounted on the closurefor sealing engagement with the sealing surface in the vehicle fillerneck, the closure retainer apparatus being axially positioned to liebetween the seal and the handle. .Iaddend..Iadd.44. The cap of claim 43,wherein the side wall is sized for insertion into the fill passagewayand the closure retainer apparatus comprises radially outwardlyprojecting ramps extending from the side wall. .Iaddend..Iadd.45. Thecap of claim 44, wherein the ramps are movable between a vehicle fillerneck-engaging position and a vehicle filler neck-disengaging position..Iaddend..Iadd.46. The cap of claim 44, wherein the closure retainerapparatus is carried by the side wall and the closure further comprisesan end closure member movably coupled to the side wall and the seal iscarried by the end closure member. .Iaddend..Iadd.47. The cap of claim46, wherein the end closure member includes an external wall axiallymovable in the vehicle filler neck relative to the side wall and theseal is mounted on the external wall. .Iaddend..Iadd.48. A capengageable with a vehicle filler neck of a vehicle fuel tank wherein thevehicle filler neck includes a mouth defining a fill passageway and asealing surface positioned to lie in the fill passageway spaced apartfrom the mouth, the cap comprising a closure for closing the vehiclefiller neck, the closure sized for insertion into the fill passagewayand having an axially inner end, an axially outer end, a side wall sizedfor insertion into the fill passageway, and closure retainer apparatusconfigured to engage the vehicle filler neck when the closure isinstalled in the vehicle filler neck to block removal of the closurefrom the vehicle filler neck, the closure retainer apparatus includingradially outwardly projecting ramps extending from the side wall, ahandle coupled to the axially outer end of the closure for moving theclosure relative to the vehicle filler neck, and a seal mounted on theclosure for sealing engagement with the sealing surface in the vehiclefiller neck, the closure retainer apparatus being axially positioned tolie between the seal and the handle, and the side wall is generallycylindrical in shape and the closure retainer apparatus comprises a lugthat extends from the cylindrical side wall and is formed for movementbetween a filler neck-engaging position and a filler neck-disengagingposition. .Iaddend..Iadd.49. The cap of claim 48, wherein three lugs arepositioned in spaced-apart relation about a circumference of thecylindrical wall. .Iaddend..Iadd.50. A cap engageable with a vehiclefiller neck of a vehicle fuel tank wherein the vehicle filler neckincludes a mouth defining a fill passageway and a sealing surfacepositioned to lie in the fill passageway spaced apart from the mouth,the cap comprisinga closure for closing the vehicle filler neck, theclosure sized for insertion into the fill passageway and having anaxially inner end, an axially outer end, closure retainer apparatusconfigured to engage the vehicle filler neck when the closure isinstalled in the vehicle filler neck to block removal of the closurefrom the vehicle filler neck, and a housing that carries the closureretainer apparatus, a handle coupled to the axially outer end of theclosure for moving the closure relative to the vehicle filler neck, aseal mounted on the closure for sealing engagement with the sealingsurface in the vehicle filler neck, the closure retainer apparatus beingaxially positioned to lie between the seal and the handle, and an endclosure member movably coupled to the housing and carrying the seal..Iaddend..Iadd.51. A cap engageable with a vehicle filler neck of avehicle fuel tank wherein the vehicle filler neck includes a mouthdefining a fill passageway and a sealing surface positioned to lie inthe fill passageway spaced apart from the mouth, the cap comprising aclosure for closing the vehicle filler neck, the closure sized forinsertion into the fill passageway and having an axially inner end, anaxially outer end, and closure retainer apparatus configured to engagethe vehicle filler neck when the closure is installed in the vehiclefiller neck to block removal of the closure from the vehicle fillerneck, a handle coupled to the axially outer end of the closure formoving the closure relative to the vehicle filler neck, a seal mountedon the closure for sealing engagement with the sealing surface in thevehicle filler neck, the closure retainer apparatus being axiallypositioned to lie between the seal and the handle, and the closureretainer apparatus are mounted for movement relative to the handle, thehandle includes a cap-release lever coupled to the closure for pivotablemovement between a horizontal cap-retaining position moving the closureretainer apparatus to engage the vehicle filler neck and a verticalcap-releasing position moving the closure retainer apparatus todisengage the vehicle filler neck. .Iaddend..Iadd.52. The cap of claim51, wherein the handle is formed to include a handle-receiving recessthat is sized to receive the cap-release lever therein when thecap-release lever is in the cap-retaining position. .Iaddend..Iadd.53. Avehicle fuel tank closure system comprisinga vehicle filler neck havinga mouth, an inside wall extending axially inwardly from the mouthinternally in the vehicle filler neck and defining a fill passageway forfluid communication with a vehicle fuel tank, the inside wall includinga sealing surface positioned to lie in the fill passageway spaced apartfrom the mouth, a closure for closing the vehicle filler neck, theclosure including a housing sized for insertion into the fill passagewayand closure retainer apparatus configured to move radially relative tothe inside wall to engage the vehicle filler neck when the housing isinstalled axially into the vehicle filler neck to block removal of theclosure from the vehicle filler neck, a handle coupled to the closurefor moving the closure relative to the vehicle filler neck, and a sealcarried by the closure for sealing engaging the sealing surface of theinside wall to form a seal therebetween to block the escape of liquidfuel and fuel vapor from the fill passageway of the vehicle filler neck,the closure retainer apparatus being axially positioned to lie betweenthe seal and the handle, the inside wall of the vehicle filler neckincludes a seal seat that extends into the fill passageway and definesthe sealing surface and the seal engages the seal seat as the, closureis moved axially inwardly during installation of the closure into thefill passageway of the vehicle filler neck, and the closure furtherincludes a compressing spring configured to press the seal away from themouth of the vehicle filler neck and against the seal seat of thevehicle filler neck during installation of the closure in the vehiclefiller neck and an end closure member axially movable in the fillpassageway relative to the housing, the end closure member includes acup-shaped mouth having a snap arm and a groove sized to receive theseal therein, the housing interacts with the snap arm and the seal ismounted in the groove. .Iaddend..Iadd.54. A vehicle fuel tank closuresystem comprising a vehicle filler neck having a mouth, an inside wallextending axially inwardly from the mouth internally in the vehiclefiller neck and defining a fill passageway for fluid communication witha vehicle fuel tank, the inside wall including a sealing surfacepositioned to lie in the fill passageway spaced apart from the mouth, aclosure for closing the vehicle filler neck, the closure including ahousing sized for insertion into the fill passageway and closureretainer apparatus configured to move radially relative to the insidewall to engage the vehicle filler neck when the housing is installedaxially into the vehicle filler neck to block removal of the closurefrom the vehicle filler neck, a handle coupled to the closure for movingthe closure relative to the vehicle filler neck, and a seal carried bythe closure for sealingly engaging the sealing surface of the insidewall to form a seal therebetween to block the escape of liquid fuel andfuel vapor from the fill passageway of the vehicle filler neck, theclosure retainer apparatus being axially positioned to lie between theseal and the handle, the inside wall of the vehicle filler neck includesa seal seat that extends into the fill passageway and defines thesealing surface and the seal engages the seal seat as the closure ismoved axially inwardly during installation of the closure into the fillpassageway of the vehicle filler neck, and the closure further includesa compression spring configured to press the seal away from the mouth ofthe vehicle filler neck and against the seal seat of the vehicle fillerneck during installation of the closure in the vehicle filler neck andthe housing defines an interior region therein, closure retainerapparatus includes a lug that extends from the housing, and the closureincludes an end closure member movably coupled to the housing andcarrying the seal thereon. .Iaddend..Iadd.55. The vehicle fuel tankclosure system of claim 54, wherein the closure retainer apparatus aremounted for movement relative to the handle and the handle includes acap-release lever coupled to the closure and formed for pivotablemovement relative to the vehicle filler neck between a horizontalcap-retaining position moving the closure retainer apparatus to engagethe vehicle filler neck and a vertical cap-releasing position moving theclosure retainer apparatus to disengage the vehicle filler neck..Iaddend..Iadd.56. A vehicle fuel tank closure system comprisingavehicle filler neck having a mouth, an inside wall extending axiallyinwardly from the mouth internally in the vehicle filler neck anddefining a fill passageway for fluid communication with a vehicle fueltank, the inside wall including a sealing surface positioned to lie inthe fill passageway spaced apart from the mouth, a closure for closingthe vehicle filler neck, the closure including a housing sized forinsertion into the fill passageway and closure retainer apparatusconfigured to move radially relative to the inside wall to engage thevehicle filler neck when the housing is installed axially into thevehicle filler neck to block removal of the closure from the vehiclefiller neck, the closure having an axially inner end and an axiallyouter end, a handle connected to the axially outer end of the closurefor moving the closure relative to the vehicle filler neck, and a sealcarried by the closure for sealingly engaging the sealing surface of theinside wall to form a seal therebetween to block the escape of liquidfuel and fuel vapor from the fill passageway of the vehicle filler neck,the closure retainer apparatus being axially positioned to lie betweenthe seal and the handle, and the seal being carried on the closureadjacent to the axially inner end. .Iaddend..Iadd.57. The vehicle fueltank closure system of claim 56, wherein the seal includes a firstportion engaging the vehicle filler neck and a second portion engagingthe closure so that the seal is compressed between the closure and thevehicle filler neck. .Iaddend..Iadd.58. The vehicle fuel tank closuresystem of claim 56, wherein the inside wall of the vehicle filler neckis formed to include a radially inwardly extending seal seat definingthe sealing surface and the closure cooperates with the seal seat of thevehicle filler neck to compress the seal as the closure is installedinto the fill passageway of the vehicle filler neck. .Iaddend..Iadd.59.The vehicle fuel tank closure system of claim 56, wherein the insidewall of the vehicle filler neck includes a seal seat that extends intothe fill passageway and defines the sealing surface and the seal engagesthe seal seat as the closure is moved axially inwardly duringinstallation of the closure into the fill passageway of the vehiclefiller neck. .Iaddend..Iadd.60. The vehicle fuel tank closure system ofclaim 59, wherein an axial distance between the mouth and the seal seatis a distance X, a radial diameter of the inside wall axially outwardlyfrom the seal seat is a distance Y, and Y is about 1.11X..Iaddend..Iadd.61. The vehicle fuel tank closure system of claim 59,wherein the closure further comprises a compression spring configured topress the seal away from the mouth of the vehicle filler neck andagainst the seal seat of the vehicle filler neck during installation ofthe closure in the vehicle filler neck. .Iaddend..Iadd.62. A vehiclefuel tank closure system comprisinga vehicle filler neck having a mouth,an inside wall extending axially inwardly from the mouth internally inthe vehicle filler neck and defining a fill passageway for fluidcommunication with a vehicle fuel tank, the inside wall including asealing surface positioned to lie in the fill passageway spaced apartfrom the mouth, a closure for closing the vehicle filler neck, theclosure including a housing sized for insertion into the fill passagewayand closure retainer apparatus configured to move radially relative tothe inside wall to engage the vehicle filler neck when the housing isinstalled axially into the vehicle filler neck to block removal of theclosure from the vehicle filler neck, a handle coupled to the closurefor moving the closure relative to the vehicle filler neck, and a sealcarried by the closure for sealingly engaging the sealing surface of theinside wall to form a seal therebetween to block the escape of liquidfuel and fuel vapor from the fill passageway of the vehicle filler neck,the closure retainer apparatus being axially positioned to lie betweenthe seal and the handle, and the closure includes an end closure membermovably coupled to the housing and the seal is carried by the endclosure member. .Iaddend..Iadd.63. A vehicle fuel tank closure systemcomprising a vehicle filler neck having a mouth, an inside wallextending axially inwardly from the mouth internally in the vehiclefiller neck and defining a fill passageway for fluid communication witha vehicle fuel tank, the inside wall including a radially inwardlyextending seal seat defining a sealing surface positioned to lie in thefill passageway spaced apart from the mouth, a closure for closing thevehicle filler neck, the closure including a housing sized for insertioninto the fill passageway and closure retainer apparatus configured tomove radially relative to the inside wall to engage the vehicle fillerneck when the housing is installed axially into the vehicle filler neckto block removal of the closure from the vehicle filler neck, a handlecoupled to the closure for moving the closure relative to the vehiclefiller neck, and a seal carried by the closure for sealingly engagingthe sealing surface of the inside wall to form a seal therebetween toblock the escape of liquid fuel and fuel vapor from the fill passagewayof the vehicle filler neck, the closure retainer apparatus being axiallypositioned to lie between the seal and the handle, the closurecooperating with the seal seat of the vehicle filler neck to compressthe seal as the closure is installed into the fill passageway of thevehicle filler neck, and an axial distance between the mouth and theseal seat is a distance X a radial diameter of the inside wall axiallyoutwardly from the seal seat is a distance Y, and Y is about 1.16X..Iaddend..Iadd.64. A vehicle fuel tank closure system comprising avehicle filler neck having a mouth, an inside wall extending axiallyinwardly from the mouth internally in the vehicle filler neck anddefining a fill passageway for fluid communication with a vehicle fueltank, the inside wall including a radially inwardly extending seal seatdefining a sealing surface positioned to lie in the fill passagewayspaced apart from the mouth, a closure for closing the vehicle fillerneck, the closure including a housing sized for insertion into the fillpassageway and closure retainer apparatus configured to move radiallyrelative to the inside wall to engage the vehicle filler neck when thehousing is installed axially into the vehicle filler neck to blockremoval of the closure from the vehicle filler neck, a handle coupled tothe closure for moving the closure relative to the vehicle filler neck,and a seal carried by the closure for sealingly engaging the sealingsurface of the inside wall to form a seal therebetween to block theescape of liquid fuel and fuel vapor from the fill passageway of thevehicle filler neck, the closure retainer apparatus being axiallypositioned to lie between the seal and the handle, the closurecooperating with the seal seat of the vehicle filler neck to compressthe seal as the closure is installed into the fill passageway of thevehicle filler neck, and an axial distance between an outermost portionof the closure retainer apparatus and an outermost portion of the sealengaging the seal seat is a distance Z and Z is about 1.94X..Iaddend..Iadd.65. A cap for use in a vehicle filler neck of a vehicletank, the vehicle filler neck being formed to include an outer mouth, afill passageway communicating with the outer mouth, a cap-retentioncavity opening into the fill passageway, and a seal-receiving seat lyingin the fill passageway spaced-apart relation to the outer mouth, the capcomprising a housing sized to fit into the fill passageway, the housinghaving an axially inner end and an axially outer end, an end closuremember movably coupled to the housing adjacent its axially inner end andcarrying a seal thereon, a handle for pushing the housing and the endclosure member into the fill passageway to seat the seal on theseal-receiving seat, the handle being attached to the housing adjacentthe axially outer end thereof, and closure retainer apparatus retainingthe housing and the end closure member in a filler neck-closing positionin the fill passageway so that the seal sealingly engages theseal-receiving seat to close the fill passageway, the closure retainerapparatus including at least one retaining lug formed for radialmovement relative to the cap-retention cavity during movement of thehousing into and out of the fill passageway. .Iaddend..Iadd.66. The capof claim 65, wherein the housing is formed to include arm receivingchannels and the end closure member includes a body, snap arms coupledto the body and extending into the arm receiving channels to movablycouple the end closure member to the housing and permit relativemovement therebetween in the fill passageway so that the housing is freeto move in an axially inward direction into the fill passageway andrelative to the end closure member upon seating of the seal on theseal-receiving seat of the vehicle filler neck. .Iaddend..Iadd.67. Thecap of claim 65, wherein each retaining lug is formed for pivotingmovement between a projected position fitting into the cap-retentioncavity and a retracted position lying outside the cap-retention cavityduring movement of the housing into and out of the fill passageway, andfurther comprising a spring yieldably biasing each retaining lug towardits projected position so that each lug snaps automatically from itsretracted position into the cap-retention cavity to retain the housingand the end closure member in the filler neck-closing position duringinstallation of the cap on the vehicle filler neck. .Iaddend..Iadd.68.The cap of claim 67, wherein the housing is a cylindrical sleeve havingan interior region and the spring is positioned to extend into theinterior region of the cylindrical sleeve. .Iaddend..Iadd.69. The cap ofclaim 68, wherein a plurality of retaining lugs are arranged inspaced-apart relation around a circumference of the cylindrical sleeveand in radially outwardly spaced-apart relation to said cylindricalsleeve. .Iaddend..Iadd.70. The cap of claim 65, wherein the housing is acylindrical sleeve and a plurality of retaining lugs are arranged inspaced-apart relation about a circumference of the cylindrical sleeveand further comprising a retaining lug actuator positioned to lie in thehousing and coupled to each of the retaining lugs to move the lugs inradially inward and outward directions with respect to the cylindricalsleeve during movement of the retaining lugs between a projectedposition fitting into the cap-retention cavity and a retracted positionlying outside the cap-retention cavity during movement of the housinginto and out of the fill passageway. .Iaddend..Iadd.71. The cap of claim70, wherein the retaining lug actuator is mounted adjacent the axiallyouter end of the housing to pivot the retaining lugs simultaneously inradially inward directions from their projected positions to theirretracted positions. .Iaddend..Iadd.72. The cap of claim 70, furthercomprising a controller and wherein the handle is formed to include anaperture and the controller extends through the aperture for engagementwith the retaining lug actuator. .Iaddend..Iadd.73. The cap of claim 72,wherein the retaining lug actuator includes an upstanding stem engagingthe controller and a toggle arm seat and corresponding cover to fastenthe retaining lugs therebetween to cause the retaining lugs to move inresponse to movement of the retaining lug actuator in the housing..Iaddend..Iadd.74. The cap of claim 73, wherein the controller is apivotable lever carried on the handle and the pivotable lever includes acam engaging the upstanding stem to move the retaining lug actuator inthe housing to control movement of the retaining lugs..Iaddend..Iadd.75. The cap of claim 73, wherein each retaining lugincludes a toggle arm fastened between the toggle arm seat andcorresponding cover and a locking arm configured to fit into the capretention cavity, the controller is a lever carried by the handle forpivotable movement relative to the housing, and the lever includes agrip handle and a cam engaging the retaining lug actuator so that thetoggle arm seat and corresponding cover moves the toggle arms to pivoteach locking arm into the cap-retention cavity in response to pivotingmovement of the lever relative to the housing. .Iaddend..Iadd.76. Thecap of claim 75, further comprising a spring extending between the endclosure member and the retaining lug actuator. .Iaddend..Iadd.77. A capfor use in a vehicle filler neck of a vehicle fuel tank, the vehiclefiller neck being formed to include an outer mouth, a fill passagewaycommunicating with the outer mouth, a cap-retention cavity opening intothe fill passageway, and a seal-receiving seat lying in the fillpassageway in spaced-apart relation to the outer mouth, the capcomprising a housing including a sleeve having an interior region, thesleeve being sized to fit into the fill passageway and having an axiallyinner end and an axially outer end, an end closure member carrying aseal thereon and being coupled to the axially inner end of the sleeve, ahandle being coupled to the axially outer end of the sleeve for pushingthe housing and the end closure member into the fill passageway to seatthe seal on the seal-receiving seat, closure retainer apparatus forretaining the housing and the end closure member in a fillerneck-closing position in the fill passageway so that the seal sealinglyengages the seal-receiving seat to close the fill passageway, theclosure retainer apparatus including at least one retaining lug mountedto the housing for movement between a projected position fitting intothe cap-retention cavity and a retracted position lying outside thecap-retention cavity during movement of the housing into and out of thefill passageway, a movable lug actuator coupled to each retaining lug,and a compression spring positioned to extend into the interior regionof the sleeve, the compression spring being configured to yieldably biaseach retaining lug toward its projected position so that is snapsautomatically from its retracted position into the cap-retention cavityto retain the housing and the end closure member in the fillerneck-closing position during installation of the cap on the vehiclefiller neck. .Iaddend..Iadd.
 8. A cap for use in a vehicle filler neckof a vehicle tank, the vehicle filler neck being formed to include anouter mouth, a fill passageway communicating with the outer mouth, acap-retention cavity opening into the fill passageway, and aseal-receiving seat lying in the fill passageway in spaced-apartrelation to the outer mouth, the cap comprisinga housing sized to fitinto the fill passageway, the housing having an axially inner end and anaxially outer end and a central core positioned to lie adjacent theaxially outer end, an end closure member including a body, snap armscoupled to the body and movably coupled to the housing to permitrelative movement therebetween in the fill passageway so that thehousing is free to move in an axially inward direction relative to theend closure member, a seal coupled to the end closure member forsealingly engaging the seal-receiving seat, a handle coupled to theaxially outer end of the housing for pushing the housing and the endclosure member into the fill passageway to seat the seal on theseal-receiving seat, closure retainer apparatus retaining the housingand the end closure member in a filler neck-closing position in the fillpassageway so that the seal sealingly engages the seal-receiving seat toclose the fill passageway, the closure retainer apparatus including atleast one retaining lug movably mounted to the housing for movementbetween a projected position fitting in the cap-retention cavity and aretracted position lying outside the cap-retention cavity duringmovement of the housing into and out of the fill passageway, a movablelug actuator arranged to lie in the housing and contact the retaininglug, and a compression spring positioned to lie in the housing and beingconfigured to yieldably bias the retaining lug toward its projectedposition so that it snaps automatically from its retracted position intothe cap-retention cavity to retain the housing and the end closuremember in the filler neck-closing position during installation of thecap on the vehicle filler neck and the central core of the housing beingformed press the lug actuator toward the end closure member to compressthe compression spring during movement of the housing into the fillpassageway and movement of the retaining lug to the projected position..Iaddend..Iadd.79. The cap of claim 78, further comprising a leverpivotably mounted on the handle and configured to move the lug actuatoragainst the compression spring to compress the compression spring andpivot the retaining lug to the retracted position so that the housing isallowed to move relative to the end closure member under a force appliedby the compression spring and the housing and the end closure member areremovable from the fill passageway. .Iaddend..Iadd.80. The cap of claim78, wherein the lug actuator further includes a cup-shaped memberengaging the compression spring and having a cylindrical side wallextending downwardly toward the seal and a toggle arm seat andcorresponding cover appended to the cylindrical side wall and the togglearm seat and corresponding cover are configured to engage and move theretaining lug. .Iaddend..Iadd.81. A cap for use in a vehicle filler neckof a vehicle tank, the vehicle filler neck being formed to include anouter mouth, and a seal-receiving seat lying in the fill passageway inspaced-apart relation to the outer mouth, the cap comprising an endclosure member including a seal for abutting the seal-receiving seatwithout contacting the outer mouth and for closing the vehicle fillerneck, a housing coupled to the end closure member and sized to extendinto the fill passageway through the open mouth, closure retainerapparatus being mounted on the housing for movement between a fillerneck-engaging position and a filler neck-releasing position, acontroller coupled to the housing, the controller including an actuatorpositioned to lie in the housing and engaging closure retainerapparatus, the actuator being configured to move closure retainerapparatus from its filler neck-engaging position to its fillerneck-releasing position, and a spring engaging the actuator and the endclosure member and configured to urge the seal against theseal-receiving seat of the vehicle filler neck to establish a sealbetween the end closure member and vehicle filler neck..Iaddend..Iadd.82. The cap of claim 81, wherein closure retainerapparatus includes at least one retaining lug mounted on the housing forpivotable movement about a pivot axis between the filler neck-engagingposition and the filler neck-releasing position. .Iaddend..Iadd.83. Thecap of claim 81, wherein the vehicle filler neck is formed to include acavity sized to receive the closure retainer apparatus, the closureretainer apparatus includes a locking arm and a toggle arm, the actuatoris coupled to the toggle arm and arranged to slide in oppositedirections in an interior region of the housing, and the controllerfurther includes a cam coupled to the housing for moving the actuator ina first direction further into the interior region of the housing topivot the retaining lug so that the locking arm of the closure retainerapparatus moves out of the cavity formed in the vehicle filler neck andthe housing and the end closure member is removable from the fillpassageway. .Iaddend..Iadd.84. A cap for use in a vehicle filler neck ofa vehicle tank, the vehicle filler neck being formed to include an outermouth, and a seal-receiving seat lying in the fill passageway inspaced-apart relation to the outer mouth, the cap comprising a housingsized to fit into the fill passageway through the open mouth, thehousing including an axially inner end facing into the fill passagewayand an axially outer end facing away from the fill passageway, an endclosure member for closing the vehicle filler neck, the end closuremember being coupled to the axially inner end of the housing andincluding a seal for abutting the seal-receiving seat, closure retainerapparatus configured to retain the housing and the end closure member ina filer neck-closing position in the fill passageway so that the sealsealingly engages the seal-receiving seat to close the fill passageway,and a compression spring having an axially inner end facing into thefill passageway and engaging the end closure member and an axially outerend facing away from the fill passageway and engaging closure retainerapparatus. .Iaddend..Iadd.85. A cap engageable with a vehicle fillerneck of a vehicle fuel tank wherein the vehicle filler neck includes amouth defining a fill passageway and a sealing surface positioned to liein the fill passageway spaced apart from the mouth, the cap comprisingaclosure for closing the vehicle filler neck, the closure being sized forinsertion into the fill passageway, the closure having an axially innerend, an axially outer end, a side wall being generally cylindrical inshape and sized for insertion into the fill passageway, and closureretainer apparatus configured to engage the vehicle filler neck when theclosure is installed in the vehicle filler neck to block removal of theclosure from the vehicle filler neck, the closure retainer apparatusincluding a lug extending from the cylindrical side wall and beingformed for movement between a filler neck-engaging position and a fillerneck-disengaging position, a handle coupled to the axially outer end ofthe closure to move the closure relative to the vehicle filler neck, anda seal mounted on the closure for sealing engagement with the sealingsurface in the vehicle filler neck, the closure retainer apparatus beingaxially positioned to lie between the seal and the handle, the closureretainer apparatus is carried by the cylindrical side wall and theclosure further comprises an end closure member movably coupled to thecylindrical side wall and the seal is carried by the end closure member..Iaddend..Iadd.86. The cap of claim 85, wherein the end closure memberincludes an external wall axially movable in the vehicle filler neckrelative to the cylindrical side wall and the seal is mounted on theexternal wall. .Iaddend..Iadd.87. The cap of claim 86, wherein threelugs are positioned in spaced-apart relation about a circumference ofthe cylindrical side wall. .Iaddend..Iadd.88. The cap of claim 87,wherein three lugs are positioned in spaced-apart relation about acircumference of the cylindrical side wall. .Iaddend.